Drill string retrieval device

ABSTRACT

Device, and method for utilizing same, for withdrawing from a borehole a section of drill string said device comprising a hollow rod with a capping member mounted on the lower end thereof adapted to fit into the upper end of the drill string to be removed and a cylindrical mesh fixed to the rod surrounding the cap and of sufficient diameter to slide over the drill string to be removed and woven so that an increase in the diameter of the upper section of the mesh results in a substantial decrease in the diameter of the lower section resulting in gripping action on the drill string. Expansion of the upper section is caused by mud flow through the rod and through ports in the capping member outwardly through the upper section of the cylindrical mesh.

United States Patent [191 Keenan, Jr.

Assignee:

Filed:

Appl. No.: 505,124

DRILL STRING RETRIEVAL DEVICE Inventor:

Bernard J. Keenan, Jr., West Chester, Pa.

Sun Oil Company of Pennsylvania, Philadelphia, Pa.

Sept. 11, 1974 U.S. Cl. 294/86.15; 294/86.1; 294/86.26

Int. Cl. E21B 31/02 Field of Search 294/86 R, 86 CG, 86.1,

References Cited UNITED STATES PATENTS Oct. 14, 1975 PrimaryExaminerEvon C. Blunk Assistant ExaminerJohnny D. Cherry [57] ABSTRACTDevice, and method for utilizing same, for withdrawing from a borehole asection of drill string said device comprising a hollow rod with acapping member mounted on the lower end thereof adapted to fit into theupper end of the drill string to be removed and a cylindrical mesh fixedto the rod surrounding the cap and of sufficient diameter to slide overthe drill string to be removed and woven so that an increase in thediameter of the upper section of the mesh results in a substantialdecrease in the diameter of the lower section resulting in grippingaction on the drill string. Expansion of the upper section is caused bymud flow through the rod and through ports in the capping memberoutwardly through the upper section of the cylindrical mesh.

US. Patent Oct. 14, 1975 Sheet 1 of2 3,912,320

US. atent Oct. 14,1975 Sheet20f2 3,912,320

FIQZ.

V DRILL STRING RETRIEVAL DEVICE BACKGROUND OF THE INVENTION 1. Field ofthe Invention This invention relates to retrieval of a cylindricalmember from a location with limited access. More particularly, itrelates to a device and method of utilizing the device whereby a secondof drill string lodged in a borehole due to breakage or other causes canbe removed so that drilling can be continued.

2. Description of the Prior Art During drilling operations it may happenthat a breakage of the drill string occurs. A lower portion of the drillstring at the end of which is secured the drilling tool is thus lost inthe well and it is practically impossible to restart the drillingoperation as long as this lower portion of the drill string has not beenrmoved.

It is thus necessary to conduct fishing operations for recovering thelower portion of the drill string. These operations are often difficultto carry out and are more expensive as they also immobilize the drillinginstallation for a long time.

The fishing devices used up to now are very complex and require cuttingoff sections on the portion of drill string to be recovered. Thisresults in a further increase of the operation time and of its cost.

It is therefore an object of this invention to provide a simple deviceavoiding the above-mentioned disadvantages and which is efficient andeasy to use.

US. Pat. No. 3,697,114 issued to Chatard et al, Oct. 10, 1972, disclosesa system simpler than the fishing procedure mentioned above andcomprising a rod with a sock-like member mounted on the lower end andmeans for axially elongating the sock-like member so as to decrease itsdiameter and grip the drill string. Yet to conduct an elongationoperation in the Chatard systern, requires a system of pistons andmoving parts all subject to jamming and malfunction, as are all movingparts, especially in a borehole environment.

SUMMARY OF THE INVENTION A device and method for retrieving a drillstring section from a borehole are now put forth which utilize a wiremesh to grip the drill string without the axial motion of the meshthereby eliminating an expensive and perhaps malfunction-prone aspect ofthe prior art and greatly simplifying the operation when compared toprior fishing operations.

The device for withdrawal of an elongated member or of a section ofdrill string from a borehole comprises a. a cylindrical member, havingan internal fluid passageway, one end of which is introduced into theborehole,

b. a capping member, fixedly attached to the end of the cylindricalmember introduced into the borehole, having an upper section and a lowersection, said upper section further comprising a series of ports throughwhich the fluid passageway of the cylindrical member is in fluidcommunication with the borehole outside of the cylindrical member andsaid lower section of a configuration adapted to fit the internaldiameter of the drill string, preferably a tapered configuration,

(I. a sheath of flexible material attached to the lower section of thecapping member so as to form a seal between the lower section of thecapping member and the drill string internal wall,

d. a cylindrical mesh of metal wires, cables or strands of a diameter,essentially greater than that of the elongated member or drill string,attached at one end to the cylindrical member and extending verticallyto enclose the capping member and an upper portion of the drill stringto be removed, said mesh woven so that a radial expansion in one sectionresults in a radial constriction in another section,

e. means for lowering the device into the borehole so that the cappingmember seals the internal passageway of the drill string,

. means for pumping drilling mud or the like through the cylindricalmember and outwardly through the ports in the upper section of thecapping member thereby radially expanding the mesh in that sectionresulting in radial constriction in the section surrounding the drillstring to be removed resulting in gripping of the drill string and g.means for withdrawing the device and thereby withdrawing the drillstring now attached thereto. In procedure, the device is lowered untilthe seal is formed and the mesh is surrounding the drill string, atwhich time, mud flow is started thereby causing the gripping actionpreviously described and allowing the drill string to be raised andremoved.

A more complete understanding of the invention can be had upon review ofthe description of the drawings and the preferred embodiment whichfollows.

DESCRIPTION OF THE DRAWING AND THE PREFERRED EMBODIMENT FIG. 1 is across-section of the device in a nongripping position.

FIG. 2 shows the device operatively disposed.

As can be seen in FIG. 1, a drill string section 1 has sheared or becomeotherwise lodged in the wellpipe or borehole 2 which has been placed inthe borehole 3.

The upper edge of the drill string is probably uneven as shown atlocation 4. The invention device is lowered into the wellpipe andcomprises a cylindrical member 5 running to the surface and having afluid passageway 6 within it. Mounted on the lower end of member 5 iscapping member 7 which is in fluid communication with 5 via passageways8 and 6 and in fluid communication with the wellpipe via ports 9. Arrowsshow the intended mud flow.

Also attached to member 5 is the mesh 10 which is fixed to member 5 atcollar 11. This cylindrical mesh extends downwardly surrounding theentire capping member at location A and extending essentially beyond itat location B. The mesh also has a collar 12 at its lower end tomaintain the integrity of its cylindrical shape. The lower face 13 ofcapping member 7 is preferably tapered so as to fit into drill string 1and form a seal. A sheath of flexible material such as rubber or softplastic 14 can be fitted on this face so as to improve the seal.

As seen in FIG. 2, the device is lowered into the wellpipe until cappingmember 7 fits into drill string 1 and forms a seal with it via face 13and sheath 14. At the same time mesh 10 slides over the drill string atlocation B. At this time mud flow as shown by the arrows is commenced.The mud flows via passageways 6 and 8 and ports 9 whereby it expands themesh radially at location A thereby constricting it radially at locationB so as to grip drill string 1. Once gripped, the entire string can beremoved by withdrawing the device w iththe drill string so attached.

The wires or cables of the mesh are of sufficient hardness to withstandthe weight of the drill string and must be of sufficient length, inexcess of about 5 yards for the total friction force to compensate forthe total weight to be removed from the well.

The invention claimed is:

l. A device for withdrawing an elongated member from a well comprisinga. a cylindrical member, having an internal passageway, the lower end ofsaid member being introduced into the well,

b. a capping member, fixedly mounted to the lower end of saidcylindrical member, having an upper section and a lower section adaptedto fit into the elongated member forming a seal therewith,

c. a series of ports in the upper section of said capping member throughwhich the fluid passageway of said cylindrical member is in internalcommunication with the well outside of said capping member,

d. a cylindrical mesh of metal wires, cables or strands, of a diameteressentially greater than that of the elongated member, attached at oneend to the cylindrical member and extending vertically downward tosurround the capping member and an upper portion of the elongatedmember, said mesh woven so that a radial expansion in one sectionresults in radial constriction in another section,

e. means for lowering the device into the borehole so that said cappingmember meets and forms a seal with the elongated member,

f. means for pumping drilling mud or the like through thecylindrical'member and outwardly through said ports thereby radiallyexpanding the cylindrical mesh in one section, resulting in radialconstriction in the section surrounding the elongated member .to beremoved resulting in gripping of said elongated member and g. means forwithdrawing the device and thereby v withdrawing the elongated memberattached thereto.

2. The device of claim 1 wherein the elongated member is a drill string.

3. The device of claim 1 wherein the lower end of the cylindrical meshfurther comprises a rigid cylindrical collar of essentially equaldiameter to the cylindrical mesh.

4. The device of claim 3 wherein the lower section of said cappingmember is of tapered configuration.

5. The device of claim 4 wherein the lower section is faced withflexible material to enhance the seal such as rubber or soft plastic.

6. The device of claim 5 wherein the elongated member is a drill string.

7. The device of claim 6 wherein the cylindrical mesh is at least about5 yards in length.

8. A method for withdrawing a section of drill string from a wellcomprising a. lowering into the well a cylindrical member having aninternal passageway,

b. capping the upper end of the drill string with the lower end of saidmember which is tapered to form a seal between it and the drill stringwalls,

c. enclosing the drill string with a cylindrical mesh of metal wires,cables or strands of a diameter essentially greater than that of thedrill string, said mesh fixed at its upper end to the cylindrical memberand extending downwardly to its lower end wherein a cylindrical collar,which slides over the drill string, is attached, 7

d. pumping drilling mud downwardly through said internal passageway andoutwardly through ports positioned above said tapered lower end wherebythe mesh is extended outwardly in the section surrounding thecylindrical member and thereby causing a constriction in the sectionsurrounding the drill string,

e. gripping the drill string with the mesh by the constriction and f.removing the drill string by raising of the cylindrical member to whichit is attached.

9. The method of claim 8 wherein the tapered end of the cylindricalmember is faced with a pliable material to enhance the seal, saidmaterial being rubber or plasllc.

1. A device for withdrawing an elongated member from a well comprisinga. a cylindrical member, having an internal passageway, the lower end ofsaid member being introduced into the well, b. a capping member, fixedlymounted to the lower end of said cylindrical member, having an uppersection and a lower section adapted to fit into the elongated memberforming a seal therewith, c. a series of ports in the upper section ofsaid capping member through which the fluid passageway of saidcylindrical member is in internal communication with the well outside ofsaid capping member, d. a cylindrical mesh of metal wires, cables orstrands, of a diameter essentially greater than that of the elongatedmember, attached at one end to the cylindrical member and extendingvertically downward to surround the capping member and an upper portionof the elongated member, said mesh woven so that a radial expansion inone section results in radial constriction in another section, e. meansfor lowering the device into the borehole so that said capping membermeets and forms a seal with the elongated member, f. means for pumpingdrilling mud or the like through the cylindrical member and outwardlythrough said ports thereby radially expanding the cylindrical mesh inone section, resulting in radial constriction in the section surroundingthe elongated member to be removed resulting in gripping of saidelongated member and g. means for withdrawing the device and therebywithdrawing the elongated member attached thereto.
 2. The device ofclaim 1 wherein the elongated member is a drill string.
 3. The device ofclaim 1 wherein the lower end of the cylindrical mesh further comprisesa rigid cylindrical collar of essentially equal diameter to thecylindrical mesh.
 4. The device of claim 3 wherein the lower section ofsaid capping member is of tapered configuration.
 5. The device of claim4 wherein the lower section is faced with flexible material to enhancethe seal such as rubber or soft plastic.
 6. The device of claim 5wherein the elongated member is a drill string.
 7. The device of claim 6wherein the cylindrical mesh is at least about 5 yards in length.
 8. Amethod for withdrawing a section of drill string from a well comprisinga. lowering into the well a cylindrical member having an internalpassageway, b. capping the upper end of the drill string with the lowerend of said member which is tapered to form a seal between it and thedrill string walls, c. enclosing the drill string with a cylindricalmesh of metal wires, cables or strands of a diameter essentially greaterthan that of the drill string, said mesh fixed at its upper end to thecylindrical member and extending downwardly to its lower end wherein acylindrical collar, which slides over the drill string, is attached, d.pumping drilling mud downwardly through said internal passageway andoutwardly through ports positioned above said tapered lower end wherebythe mesh is extended outwardly in the section surrounding thecylindrical member and thereby causing a constriction in the sectionsurrounding the drill string, e. gripping the drill string with the meshby the constriction and f. removing the drill string by raising of thecylindrical member to which it is attached.
 9. The method of claim 8wherein the tapered end of the cylindrical member is faced with apliable material to enhance the seal, said material being rubber orplastic.